1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB
2、ED HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS (MSDS) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 2003, 2007 UOP LLC. All rights reserve
3、d. Nonconfidential UOP Methods are available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA. The UOP Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service at serviceastm.org, 610.832.9555 FAX, or 610.83
4、2.9585 PHONE. Particle Size Distribution of Powders by Laser Light Scattering UOP Method 856-07 Scope This method is for determining the particle size distribution of powders and slurries using laser light scattering. Most applications are for particle sizes in the 1 to 100 m range, but the instrume
5、nt is capable of measuring particles from 0.02 to 2800 m. Samples are analyzed as received or prepared using sonication to disperse agglomerated particles. Reference UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method Forward light scattering is used as the basis fo
6、r measurement of particle size distribution. The instrument incorporates three lasers to measure the particles over the entire size range. A beam of laser light is projected through a circulating stream of particles and the intensity of the resultant diffraction patterns is measured by a photodetect
7、or. The intensity of the detected light at various angles is proportional to the number and size of the particles. The diffraction patterns are processed using optical models selected by the operator. The particle size distribution is presented in histogram format. The data are also summarized to in
8、clude mean and median diameter and other particle characteristics. Apparatus References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Beaker, polypropylene, 30-ml, VWR, Cat. No. 13915-067 Bottle, wash, polyethylene, 1000-mL, VWR, Cat.
9、 No. 16651-664 Ultrasonic Probe, Branson, Model S-250D, VWR, Cat. No. 33995-594 Particle size analyzer, Microtrac, Model S3500 Spatula, double blade, flat end, VWR, Cat. No. 57952-005 Stir plate, VWR, Cat. No. 58940-158 2 of 6 856-07 Stir bar, VWR, Cat. No. 58948-988 Reagents and Materials Reference
10、s to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Surfactants and Dispersing Aids, Assorted Cationic, Anionic, Non-Ionic: Isopropanol, Photoflo, TSPP (Tetra Sodium Pyro Phosphate), and TritonX-100, VWR, Cat. Nos. (consecutively, BDH1133
11、-1LP, GRKK146-4510, JT3850-1, and 82022-980). Typical concentrations are less than 0.1 weight percent. Water, deionized, or as recommended by the manufacturer Water, for sampling system, flow rate, 35 L (5 gal) per minute; pressure 30-100 psig (210-690 kPa) The Microtrac analyzer has its own filter
12、and pressure regulator. If the water supply contains excessive particulate matter, installation of a pre-filter is advisable. Water is the typical dispersing medium for the majority of sample types. Water with surfactants may also be used if the suspension is unstable. With the use of additional acc
13、essories from the manufacturer, non-aqueous liquids or air may also be used as the dispersing medium. Procedure The analyst is expected to be familiar with general laboratory practices and the equipment being used. This Procedure section gives specific instructions for the Microtrac analyzer listed
14、in Apparatus. If a differernt analyzer is used, use these instructions as a guide, along with the instructions from the instrument manufacturer, to perform the analysis. 1. Install the analyzer according to the manufacturers instructions. Complete the initial operating check and startup procedure as
15、 described in the Instrument Operating Manual to verify instrument operation. Once this is completed, it need not be done again unless service is required. The Microtrac S3500 software is entirely automated. 2. Standard analysis methods can be developed for each material type that will reduce the se
16、t up and analysis time. Enter the parameters listed in Table 1 for the typical “UOP Standard Analysis.” Enter other parameters in different analytical method files as needed for the sample types to be analyzed. See the Instrument Operating Manual for instructions on how to set up and store multiple
17、analysis methods. Automated background correction can also be initiated using the Set Zero function prior to each sample that is analyzed. Sample Preparation Obtain a representative sample of the powder or slurry to be tested. Samples may be analyzed without pretreatment if the assumption can be mad
18、e that the sample contains no particles larger than the upper limit of the selected range. 1. Fill a 30-mL beaker containing a stir bar with deionized water to the 27 ml mark. Using a spatula, place approximately one gram of sample into the beaker. If sonication is not required, proceed to Sample An
19、alysis. 2. Transfer the beaker to the stir plate with the ultrasonic probe and turn on the stir plate. Align the probe tip with the side of the beaker at the 10 ml mark. Sonicate using the standard conditions of 90 watts for four minutes, setting the timer on the ultrasonic probe. 3 of 6 856-07 Samp
20、le Analysis 1. Select the instrument to be used from the tool bar. Select Measure Select Instrument S3500/3000. 2. Recall the appropriate analysis method from the drop down list by selecting Set Up and recall the method from saved methods (see Procedure Number 2). 3. Run Background Correction (Set Z
21、ero) and initiate the sample analysis by selecting “Auto” from the tool bar. 4. Add the prepared sample to the analysis chamber when prompted by the software. Follow the on screen instructions to determine the amount of sample required. The instrument will automatically start the analysis when the c
22、orrect sample concentration is measured. 5. The sample chamber will automatically rinse, disposing of the sample down the drain, following the completion of the analysis sequence. Since the sample prep is dilute with low solids and neutral pH, it is acceptable to discard the small amount used for an
23、alysis down the drain. The remainder of the sample prep is allowed to settle, is decanted, and the solids are dried and diposed of in Industrial Waste. Check local regulations to confirm proper disposal procedures. Table 1 Instrument Parameters: UOP Standard Analysis Timing Set Zero Time (s): 30 Run
24、 Time (s): 30 Number of Runs: 3 Particle Information Transparency: Absorbing Refractive Index: N/A Shape: Irregular Perspective Progression: Standard Distribution: Volume Minimum: 0.0215 Maximum: 1408 Residual: Disabled Percentile: 10, 25, 50, 75, 90 Fluid Information Water Refractive Index: 1.333 S
25、DC/ASVR (Options) SDC/ASVR Information: Default New Parameters: Default Control Number of Rinses: 4 De-aeration Cycles: 4 Flow Rate (%): 35 Ultrasound (%): 30 Ultrasound Time (s): 120 SDC/ASVR (Auto Sequence) Fill/Rinse: Disable Perform Set Zero: Enabled Continue Valid: Enabled Auto Sequence: 1 Samp
26、le Loading UltraSound: None Pre-Run Circ (s): 60 Calculations All calculations are carried out by the software and printed automatically using Adobe. Typical data reports are shown in Figures 1 and 2. ASCII and other file types may also be generated for electronic data transfer. Results are reported
27、 to three significant figures. 4 of 6 856-07 Figure 1 Typical Report, Small Particles 5 of 6 856-07 Figure 2 Typical Report, Large Particles 6 of 6 856-07 Precision Precision statements were determined using UOP Method 999. Repeatability and Intermediate Precision A nested design was carried out for
28、 determining particle size of two different samples with two analysts in one laboratory. Each analyst carried out tests on two separate days, performing two tests each day per sample. The total number of tests for each of the two samples was eight. The precision data are summarized in Table 2. Two t
29、ests performed by the same analyst on the same day should not differ by more than the repeatability allowable difference with 95% confidence. Two tests performed in one laboratory by different analysts on different days should not differ by more than the intermediate precision allowable difference w
30、ith 95% confidence. The data in Table 2 are a short-term estimate of repeatability. When the test is run routinely, a control standard and chart should be used to develop a better estimate of the long-term repeatability. Table 2 Repeatability and Intermediate Precision, m Repeatability Intermediate
31、Precision Sample Mean Size Within- Day esd Allowable Difference Within- Lab esd Allowable Difference Zeolite Catalyst 1.86 94.07 0.005 0.58 0.02 2.29 0.008 0.46 0.03 1.66 Reproducibility There is insufficient data to calculate reproducibility of the test at this time. Time for Analysis The elapsed time for one analysis is 0.25 hour. The labor requirement is 0.25 hour. Suggested Suppliers Microtrac Inc., 148 Keystone Drive, Montgomeryville, PA 18936, VWR Scientific, 1310 Goshen Parkway, West Chester, PA 19380,
